Centrifugal switch mechanism



Dec. 1, 1936.

V. WEBER CENTRIFUGAL SWITCH MECHANISM Filed June 6, 1935 2 Sheets-Sheet 1 INVENTOE V/crm? WEBER. oiouaa.

Arr-o ENE Y.

D60 1, 1936. v WEBER 2,062,736

CENTRIFUGAL SWITCH MECHANISM Filed June 6, 1935 2 Sheets-Sheet 2 /NVEN70E:

VICTOR WEBER.

Hrroe/vEK Brliama.

Patented Dec. \1. 1936 UNITED STATES PATENT OFFICE I 2,062,736 CENTRIFUGAL SWITCH ZMECHANISM Application June 6, 1935, Serial No. 25,268

16 Claims. (Cl. 200-80) This invention relates to electric switches and is particularly adapted to centrifugally operated switches. As disclosed, the device may be applied to a rotor having means movable in response to the speed thereof, which movable means actuates the switch. It, therefore, lends itself to the control of the starting circuit of a motor, that may be out out as soon as the motor reaches predetermined speed. It is an object of this invention to provide such a device that is simple in operation, easy to make, inexpensive, and having a minimum number of parts. It is another object of this device to provide such a switch providing continuousand substantially constant contact pressure throughout the time the switch is closed. T

It is a further object of this invention to provide a plurality of levers and a spring for deter- 2 mining the position of these levers, and for using the same spring to establish the breaking of con tact.

It is a further object to provide a switch of this kind which, in its operation, has a wiping action of the contact elements.

It is another object to provide a switch of this kind having no change in direction of forces upon the moving parts during the acts of making and breaking contacts, wherefore, the switch is not noisy.

It is an additional object of this invention to avoid the necessity of employing flexible wire connections between moving and stationary parts, this being avoided by designing the device so that the pivot pressure between the movable and fixed membersis a multiple of contact point pressure and does not vary appreciably during the operation. I

Further advantages will appear in the description herebelow.

In the drawings:

Fig. l is an edge elevation partly in section of the switch applied to a rotor, the rotor being stationary.

Fig. 2 is a view similar to Fig. 1, but with the rotor moving and hence the centrifugal elements extended.

Fig. 3 is a section on'the line 3--3 of Fig. 1.

Fig. 4 is a section on the line 4-4 of Fig. 1.

Fig. 5 is a section on the line 55 of Fig. 2.

Fig. 6 is a vertical section through the switch proper, the actuating mechanism being removed.

Fig. 7 is a view of the back plate of the switch mechanism.

This switch is adapted to be employed, for example, on a machine here shown as comprising a stator Ill and a rotor I I, the rotor being mounted on and rotating with a shaft l2. The end housing of the machine is designated at 13 and it has therein a journal l4 supporting the shaft l2. 5 Studs l5 are on the end plate l3 and they are adapted to receive and support the switch proper, such as is shown in Fig. 6. The switch proper may include a securing plate Hi to assist in fastening the device to the housing. 10

Over this is mounted a base I'I made of nonconducting material, shown in detail inFig. 7. Extending through this base I I is a U-shaped contact element I8 to which is secured one side of a circuit as at IS. .The U shaped plate has cars 15 20 projecting through suitable openings 2|, as shown in Fig. 7, to the rotor side of the base H. A second U-shaped contact member 24 is secured also to the base I! and out of contact with the member l8. The other side of the circuit, as at 20 25, is fastened in conducting relation to the plate 24. The member 24 has cars 26 extending through suitable openings 21 to the rotor side of the base member l'l. Pivoted in the ears 20 is a lever 28, the pivot being adapted to conduct elec- 2 tricity from the cars 20 into said lever 28. At one end the lever is provided with a contact pole 29'. It is likewise provided with a bent over portion 30 that maintains the pole 29 at, a ll times spaced at least a given distance from the base I1. 30 Pivoted in the ears 26 is a longer lever 3|, the pivots for which are provided by turned up arms 32 engaging in ears 26. At one end of the lever 3i and in cooperative relationship with the contact 29 of the lever 28, is a contact 33. Between the 5 two levers and also located between the pivots thereof is a spring 34 insulated from one oi. the levers as by insulation 35, here shown as being on lever 31. Depressions 36, formed, for instance, by stamping, in the two levers are designed to main- 40 tain the insulation and the spring in proper posi-. tion. It will be observed that the lever 28 is a lever of the first class, whereas lever 3| with respect to the spring action is a lever of the third class. The lever 3| at its end opposite the con- 45 tacts is bifurcated, having two arms 31 that straddle the rotor shaft I2. From Fig. 7 it will also be apparent that the base plate I likewise straddles this shaft. These arms 31 are bent at their outer ends, as shown at 38 in Fig. 6, for the pur- 50 pose to be shown hereafter. It may be noted, however, that the switch actuating pressure is applied to the portions 38 whence the lever 3| pivots about its pivots 32, moving the contact 33 against the spring to touch the contact 29. The 56 spring urges both levers in the same direction of rotation. Hence the positive movement of lever 3| against the action of the spring 34 is effected by force directed against portions 48. Then, when the contact a touches contact 29, any further movement of the lever 3i will force the lever is counterclockwise also against the spring 34. It will be seen, therefore, that the spring 34 urges both levers out of contact when no force is applied at 38, but when such force is applied. causing m'ovementoLthe lever Ii, the spring urges the lever 28 into intimate contact with the lever ii, at their respective contacts 29 and 33.

It is further to be observed that the compression of the spring 34 by movement of the levers is relatively small compared to the initial compression thereof. By this means, a substantially constant force acting on the contacts is effected.

The actuating mechanism for this switch includes a fixed element 44 secured to the rotor ii of the motor. This fixed member 40 has upstanding end plates 4 i The member is also adapted to receive the shaft i2 and be placed thereover. Centrifugally weighted bell cranks 42- are pivoted as at 43 to the end plates 4i of the member 40. These bell cranks carry cross rods 44 on their inner ends. A sleeve 45 fits slidably over the shaft l 2, and is provided with a cut out upstanding portion 46 in which the cross bars 44 engage. A spring 41 acts between the fixed member 40 and the upstanding portion 44 and tends to force the sleeve member 45 outwardly from the rotor ll. of course, it will be understood that the centrifugal weights in swinging out force the sleeve toward the rotor against the spring 41.

The operation of the device is as follows:

When the rotor is not moving. as shown in Fig. l, the centrifugal weights42' are held inwardly parallel to the shaft by means of the spring 41 that forces the sleeve member 44. and consequently rods 44, outwardly. The upstanding portion 46 of the sleeve 4| then engages the up standing bent portion 34 of the lever 8|, pivoting this lever about its pivots I! so that the contact 83 engages the contact II and lifts the lever 2| against the action of the spring 34. It will be seen that the spring 84 therefore has the double function of urging the contact 2. into close contact with the contact 33 when the lever Ii is raised, and also, as will be shown hereafter, of tending to'separate the two levers. In this position, the circuit from I! to II is closed through ears II, levers 24 and contact 20 to contact 44. lever ii, and ears 24. This may close the starting circuit for the motor. As the motor comes up to speed, the weights 42 swing outwardly and, by means of the rods 44, force the sleeve 44 toward the rotor and away from the lever Ii. This permits the spring 34 to press the lever 3i downwardly, followed by the lever 24, and as soon as thelug 30 engagesthebase l'l,theleverllis stopped. During this action of course there will be a substantially constant and continuous force acting to urge the contacts together, until the lever 24 is halted. The contacts 29 and 83 are in face to face engagement at the point of halting of the lever 24, and further movement of the aoeavac upon the motor's reaching a predetermined speed. In closing the switch, the contact 38 first comes into contact with the pole 2! without moving the lever 24. As the outward movement of the contact II continues, this contact is caused to wipe across the contact 20 by virtue of the greater radius of curvature of the lever 3! than that of the lever 24. This wiping action insures'a good electrical contact between the two switch poles. And during the entire operation there is always a force acting in the same direction to urge both of the levers into contact with their respective ears by means of their pivots. This insures good conduction of the electricity into or 'out of the levers, and eliminate'sthe necessity of providing separate flexible conductors for each lever.

Wherefore it will be understood that a device has been provided that is simple in construction and operation,Jiritira. minimum number of parts and oted thereto, said levers overlapping, a spring means for. urging one lever toward contact with the other, and the other away from contact with the first.

2. In a switch mechanism of the kind described, as base, a pair of levers pivoted thereto, a contact on each lever, said contacts being adapted to be brought into registry, and said pivots of said respective levers being at different distances from said contacts, whereupon when said levers are moved with said contacts contiguous to each other, one contact will wipe across the other.

3. In a switch mechanism of the kind described, a base, a pair of levers pivoted thereto and both movable thereon. a contact on each lever, said contacts being adapted-to be brought into registry, said contact arms of said levers being of diiierent lengths, whereby when said levers are pivoted said contacts are brushed one across the other, and said contacts having fiat faces adapted to register coplanarly at the instant preceding the complete separation of the contacts.

4. Ina device of the kind described, a base plate, a first lever pivoted thereto at a point between the ends thereof, a second lever pivoted in like manner, said levers having contiguous end portions, resilient means ens s s between said levers, and acting on one of them outside of its pivot and the other inside of its pivot with respect to saidcontiguous end portions whereby said resilient means me both levers in the same pivotal direction. I

5. In a switch mechanism, a base-plate. means pivoting a' pair of levers thereto, said levers all said pivot means comprising conductors, said leversbeingmovablewith respectto thebase.and means urging said levers into contact with their pivoting means constantly during the movement of the levers, whereby uninterrupted currents of electricity may flow through said pivot means into said levers.

6. Inaswitchmechanismabase'plateofnonconducting material, two pairs of pivot elements extending upwardly from said base member, and constituting two pivot devices. a lever pivoted in each pivot device, means for urging said levers into close contact with their respective pivot devices continuously during oscillation of said levers,wherehyelectriccurrentmaybepassedinto g said levers through said pivots, said means also urging both said levers toward predetermined positions about their respective pivots.

'7. In a device of the kind described, a base member, a lever pivoted intermediate its ends to said member, a second lever pivoted to said member and extending for a distance alongside said first lever, and said levers having registerable end portions, said first lever extending at its opposite end beyond said second lever, whereby pressure upon such free end causes the other end to contact said shorter lever, and means for urging said shorter lever into contact with said longer lever at their contiguous ends.

8. In a device of the kind described, a base member, a first lever pivoted thereto, a second lever independently and fixedly pivoted to said member alongside said first lever, means urging both levers to pivot in the same direction, and means limiting the movement of one lever whereby, upon moving said first lever against said urging 'means, it may be brought into contact with said second lever, said levers being then adapted to move together, and said urging means urging said second lever against said first lever.

9. In a device of the kind described, a base member, a first lever pivoted thereto, a second lever pivoted to the base member independently of said first lever and lying alongside said first lever and adapted to contact therewith, an electrical contact on each lever at said point of contact, means urging said levers toward said base member at their contiguous ends, and stop means on one lever arresting its movement toward the base, whereby the other lever may move out of contact therewith and separate said electrical contacts.

10. In a. device of the kind described, a base member, a pair of levers independently pivoted thereto, one lever overlying the other lever, and adapted to contact therewith, said levers being pivoted at different distances from their contiguous end portions whereby, when pivoted together, onewill wipe across the other, and spring means acting between said levers and between said respective pivots whereby to urge said levers in the same direction.

11. In a device of the kind described, a base member, a pair of levers pivoted thereto, one lever lying alongsidethe other lever for at least aportion of the length of the latter, and said levers being adapted to contact with each other adjacent one end of one of them, the pivot means for said levers being spaced at different distances from said contact point, spring means acting between said levers at a point between said two pivot means, and tending to urge both levers to pivot in the same direction, and stop means on one lever arresting its movement and permitting the other lever to move away therefrom.

12. In a switch mechanism, a base plate, a pair of U-shaped members mounted on said base plate in spaced relation to provide two pairs of upstanding ears, two levers, one pivoted in eachpair of ears, said levers lying alongside each other for at least a portion of the length of one of them, and adapted to contact adjacent the end of one of them, and means for (1) m'ging said levers apart, (2) urging one of said levers toward the other, and (31 urging both of said levers into intimate contact with their respective ears to provide good conductivity between said ears and said levers.

13. In a mechanism of the kind described, a. pair of members one of which is differentially movable relative to the other, a switch mechanism on one member, and an actuating device on theother, said switch member including a base, a pair of levers pivoted thereto and adapted to contact each other at one point, said levers being pivoted at different distances from said point of contact, means urging both of said levers to pivot in one direction, said actuating device including an element adapted in response to the operation of said member positively to move one end of one of said levers toward the contiguous end of the other, against said-urging means, and said urging means then acting to force said other lever into contact with said one lever.

14. In an electric machine having a movable member and a fixed member, a switch mounted on said fixed member, actuating mechanism for said switch mounted on said movable member, said switch including a base, two levers pivoted thereto and adapted to contact with each other, means acting between said levers and urging both of them to pivot in one direction, one of said levers extending adjacent said actuating means, said actuating means having an element movable in response to the speed condition of said movable member against said lever to urge it to pivot against said urging means and into' contact with said other lever, said urging means then acting to force the other lever strongly against said one lever, and said actuating means operating in response to other speed conditions of said movable member to move away from said lever, whereby said urging means may move said levers and they may become out of contact with each other.

15. In an electrical switch mechanism, a base member, a first lever pivoted intermediate its ends to said base member, a contact point on one end of said lever,a second lever pivoted to said base intermediate its ends and having a contact point on one end, said second lever overlying said first lever whereby the contact points on both may be brought together, the pivot of said second lever being between the contact point and pivot point of the first lever whereby the free end of the second lever extends between said contact point and said pivot point of said first lever, and. means engaging said first lever between said two points and said free end of said second lever, to urge said second lever toward said first lever and said 1 of the second lever will break it away from said contact.

VICTOR WEBER. 

